Fluid operated apparatus



U Feb. 25, w BROWN ET AL 3,429,324

FLUID OPERATED APPARATUS Filed Feb. 16, 1965 INVENTORS Wayne R. Brown Terence J. Co

Robert w. Van Ti/burg BY i A TTORNE'Y United. States ABSTRACT OF THE DISCLOSURE A fluid operated apparatus for providing signals at predetermined time intervals is disclosed. The apparatus embodies a fluid amplifier that operates a means, such as a two-stage diaphragm :e, for measuring a predetermined volume of fluid which means control the output from the apparatus, the output being a portion of the amplifier fluid stream.

This invention relates to fluid operated systems and more particularly to a fluid operated apparatus which can provide signals at predetermined time intervals, but is not limited to such applications.

The fluid operated apparatus of this invention may be used as a timer, analog signal to digital signal converter, or the like. For purposes of simplicity the invention will be described in terms of a timer.

In the prior art there are many kinds of timing devices. The most common of these are the electrical, electronic, and mechanical timers. There are, however, inherent disadvantages in each type of prior art timer. Known mechanical timing devices have the disadvantage of requiring many moving parts and springs, which parts require precision fabrication. Wear, friction, and thermal expansion aflects the functioning of such timing devices as well as their accuracy.

Electrical or electronic timing devices on the other hand, require constant sources of electrical energy. Such sources of energy may not be available and such energy need not be the most desirable type under particular operating conditions. Furthermore, such devices do not have long operating lives.

In the fluid operated apparatus of this invention, a bistable fluid amplifier is employed. In such a fluid amplifier, a fluid stream, hereinafter referred to as the power stream, issues into an interaction chamber from a nozzle or orifice constructed such that the power stream is well defined in space, which stream is directed towards a receiving aperture system by the pressure distribution in the power stream boundary layer region. This pressure distribution is controlled by the wall configuration of the interaction chamber, the power stream energy level, the fluid transport characteristics, the back loading of the amplifier outlet passages, and the flow of control fluid to the boundary layer region. In accordance with Bernoullis theorem, the high velocity power stream issuing from the nozzle creates regions of low pressure adjacent the interaction chamber walls and this together with the configuration of the interaction chamber in part cause the power stream to lock-on to one side wall and remain in the locked-on condition without any control fluid flow. Control fluid nozzles are provided at the interaction chamber generally at right angles to the power stream. The power stream can be deflected to the opposite wall of the interaction chamber by a control fluid flow and lockon thereto as heretofore described and remain there even after the control fluid flow is stopped. The apparatus is provided with two outlets or fluid recovery apertures or passages facing the power stream, which outlet passages atent O 3,429,324 Patented Feb. 25, 1969 are arranged such that when the power stream is lockedon one wall, all of the fluid of the power stream is directed to one of the outlet passages, and when it is locked-on the other wall, all of the fluid of the power stream is directed to the other of the outlet passages. The fluid so directed to either or both of the passages may be delivered to utilization devices as desired.

It is an object of this invention to provide an economical fluid means of obtaining signals at predetermined time intervals.

Another object of this invention is to provide signals at predetermined time intervals independent of any pressure or other condition changes at the point of utilization of the signals.

A further object is to provide a precision timer with a minimum of moving parts.

Still another object is to provide a timer with rapid response characteristics.

A still further object is to provide a fluid timer, the timing intervals of which can be rapidly and accurately changed over a wide range.

Still another object is to provide an apparatus for obtaining variable frequency output signals.

Broadly according to the present invention a fluid operated apparatus is provided comprising a source of pressurized fluid, a bistable fluid amplifier of the type having interconnected fluid passages whereby a well defined high energy fluid stream may flow from an inlet aperture to one of two outlet passages, control means for alternately switching the fluid stream from one of the outlet passages to the other, first and second apparatus outlet means, means for alternately directing a first portion of the fluid stream to the first of said apparatus outlet means and then to the second apparatus outlet means in response to said control means, fluid operated means for measuring a predetermined volume of a second portion of the fluid stream at a regulated rate such that said volume will be measured in a predetermined desired interval of time, the control means being responsive to the fluid operated means in such manner that the control means cause said fluid stream to switch to the other of the outlet passages when said volume is measured, and means for resetting the fluid operated means.

Additional objects, features, and advantages of the present invention will become apparent to those skilled in the art from the following detailed description and the attached drawing on which, by way of example, only the preferred embodiments of this invention are illustrated.

FIGURE 1 is a diagrammatic illustration of the fluid apparatus of this invention.

FIGURE 2 is a fragmentary plan view illustrating another embodiment of this invention.

FIGURE 3 is a fragmentary cross sectional view illustrating another means for regulating fluid flow.

FIGURE 4 is a fragmentary cross sectional view illustrating still another means for regulating fluid flow.

The apparatus of this invention is suitable for use with either compressible fluids such as air, nitrogen or other gases, or incompressible fluids such as water or other liquids. This invention is not limited to any particular fluid.

Referring to FIGURE 1, in the fluid timer of this invention, a bistable fluid amplifier 10 is shown having interconnected fluid passages whereby a pressurized fluid may flow from a suitable source, not shown, through inlet aperture 11 and then through power or inlet nozzle 12. The pressurized fluid emerges from nozzle 12 as a well defined high energy power stream which enters interaction chamber 14 and passes to either of two amplifier outlet passages 16 and 18. Control fluid nozzles 20 and 22 are provided at the interaction chamber. The walls of the interaction chamber of a bistable fluid amplifier are formed, in a manner well known to one familiar with the art, so that the power stream is caused to lock-on to one side wall and remain in the locked-on condition without any control fluid flow. The power stream can be deflected to the opposite Wall of the interaction chamber by a control fluid flow and remain locked-on even after the control fluid flow is stopped. In addition, vents or bleeds 21 and 23 are provided in connection with outlet passages 16 and 18 respectively, to permit entrainment flow for the power stream in a manner well known to one familiar with the art.

A pair of two-stage diaphragm valves 24 and 26 are shown connected to fluid amplifier 10. The first stage of valve 24 comprises pressurizing chamber 28 and fluid flow control chamber 30. Diaphragm 32 separates these two chambers. The second stage of valve 24 comprises pressurizing chamber 34 and fluid flow control chamber 36. Chambers 34 and 36 are separated by diaphragm 38. Control chamber 30 is connected to pressurizing chamber 34 by means of port or opening 40, while control chamber 36 is connected to control nozzle 22 by means of member or tube 42. Control chambers 30 and 36 are open to ambient by means of vent ports 44 and 46 respectively. Pressurizing chamber 28 is connected to amplifier outlet passage 16 by means of members or tubes 48 and 50, while pressurizing chamber 34 is also connected to passage 16 by tubes 48 and 50 together with members or tubes 52 and control valve 54.

The first stage of two-stage diaphragm valve 26 comprises pressurizing chamber 56 and fluid flow control chamber 58, which chambers are separated by means of diaphragm 60. The second stage of valve 26 comprises pressurizing chamber 62 and fluid flow control chamber 64, which chambers are separated by means of diaphragm 66. Control chamber 58 is connected to pressurizing chamber 62 by means of port or opening 68, while control chamber 64 is connected to control nozzle by means of member or tube 70. Control chambers 58 and 64 are open to ambient by means of vent ports 72 and 74 respectively. Pressurizing chamber 56 is connected to amplifier outlet passage 18 by means of members or tubes 76 and 78, while pressurizing chamber 62 is also connected to passage 18 by tubes 76 and 78 together with members or tubes 80 and control valve 82.

Signals from the timer are available at timer outlets 84 and 86 as hereinafter described.

It will be readily understood by one familiar with the art, that although the apparatus of this invention has been described having a pair of two stage diaphragm valves, the first stage of either or both of these valves may be replaced by a piston device, ball valve, or the like, while the second stage of either or both of these valves may be replaced by a piston device. In addition, the apparatus may also employ single-stage diaphragm valves, however, such an apparatus will have less sensitivity and will require greater physical size for the pressurizing chamber.

The operation of the timer of this invention is as follows. When a source of pressurized fluid, such as compressed air for example, is connected to fluid amplifier inlet 11, a well defined high energy power stream emerges from nozzle 12 and locks-on to either of the outer walls of the inverted V formed by outlet passages 16 and 18, specifically the left wall of outlet passage 16 or the right wall of outlet passage 18. For the purposes of this description it is assumed the power stream will lock-on the left wall of outlet passage 16 and flow in tube 48. A portion of this stream will pass through tube 50 and enter pressurizing chamber 28 of the first stage of two stage diaphragm valve 24. This portion of the stream will accumulate in chamber 28 causing diaphragm 32 to expand. A second portion of this stream will pass through tube 52 and control valve 54, and enter pressurizing chamber 34. The amount of the stream that enter chamber 34 is at least in part controlled by the setting of control valve 54. At the outset any fluid that enters chamber 34 will be exhausted through opening 40 and vent port 44 to ambient, and none will accumulate in chamber 34. As the volume of fluid accumulates in chamber 28, diaphragm 32 will continue to expand until opening 40 is closed off whereupon that portion of the stream which passes through control valve 54 will begin to accumulate in pressurizing chamber 34 since it can no longer be exhausted. As this second volume of the stream fluid accumulates in chamber 34, diaphragm 38 will expand until the opening of tube 42 is closed 0E.

While the two volumes of fluid are being accumulated in chambers 28 and 34, the power stream continues to flow from nozzle 12, through interaction chamber 14 and outlet passage 16, which flow, in accordance with Bernoullis theorem, creates a low pressure within interaction chamber 14 causing a gentle flow of ambient fluid through vent port 46, chamber 36, tube 42, and control nozzle 22 into the interaction chamber. Once the opening to tube 42 is closed off as hereinabove described, tube 42 becomes partly evacuated by the low pressure of the interaction chamber. A pressure gradient is then created between the ambient pressure in tube 70 and nozzle 20, which are open to ambient through chamber 64 and vent port 74, and the low pressure in tube 42 and nozzle 22. This pressure gradient is similar to that which could be created if an exterior source of pressurized control fluid would be connected to a control nozzle. Such a pressure gradient causes the power stream to be deflected to the opposite wall. In the instant example, the power stream is deflected and caused to lock-on to the right wall of outlet passage 18. At this point the power stream no longer flows in outlet passage 16, rather flows in outlet passage 18.

When flow in outlet passage 16 stops, the pressure in chamber 28 decreases and diaphragm 32 no longer closes off opening 40. The fluid in chamber 34 is then exhausted through vent port 44. The fluid in chamber 28 is also exhausted by partly flowing through valve 54 and its connecting tubes, to chamber 34, and then through vent port 44, and partly flowing through tubes 50 and 48, and then through vent or bleed 21. In this manner valve 24 is reset and ready to begin the cycle over again when the stream is thereafter deflected to lock-on to the right wall of passage 16.

In the meantime, a portion of the power stream will pass from outlet passage 18 through tubes 76 and 78 to pressurizing chamber 56 and accumulate therein expanding diaphragm 60 until opening 68 is closed off. A second portion of the stream flows through tubes 80 and control valve 82 to pressurizing chamber 62 Where at first this second portion exhausts to ambient through vent port 72 and then, when opening 68 is closed off, accumulates in chamber 62 thereby expanding diaphragm 66 until the opening to tube 70 is closed off. When the opening to tube 70 is closed off the power stream will be deflected, in the manner hereinabove described, and will lock-on to the left wall of passage 16, and thereafter valve 26 will reset in a manner described in connection with valve 24.

The signals from the timer are available at timer outlets 84 and 86 as pressure changes therein, and/0r fluid flows therethrough, as a result of the power stream flowing first in one of outlet passages 16 or 18 and then in the other. Timer outlets 84 and 86 are connected to utilization or sensing devices, such as diaphragm controlled valves, other fluid amplifiers, piston operated devices, or any mechanical pressure operated devices.

A first timing interval is obtained by the sum of the periods of time necessary to accumulate a first volume of fluid in the pressurizing chamber 28 and then to accumulate a second volume of fluid in pressurizing chamber 34, of valve 24. The first volume is that required to expand diaphragm 32 to the point of where it closes off opening 40, while the second volume is that required to expand diaphragm 38 to the point where it closes off the opening to tube 42. A second timing interval is similarly obtained by the functioning of valves 26 and 82. It is noted that the interval of time controlled by valves 24 and 54 need not be the same as that controlled by valves 26 and 82, since the intervals of time may be regulated by control valves 54 and 82, and since the intervals of time are also a function of the characteristics of valves 24 and 26, such as chamber volumes, diaphragrns, and the like.

As will be readily understood, for proper functioning of the timer of this invention the utilization device which is connected to the timer outlets must provide suflicient load or resistance to result in a pressure in chambers 28 and 56 adequate for the operation of the respective diaphragm valves.

It is seen that the timer of FIGURE 1 will be sensitive to load changes, that is the time intervals will be affected by pressure or other condition changes at the point of utilization. Although the time intervals will remain con stant for any given load, the timer can nevertheless be made independent of any pressure or other condition changes at the point of utilization by providing a feedback isolator 88 upstream of the timer outlets 84 and 86, as illustrated in FIGURE 2. Such a feedback isolator maintains the conditions of the upstream fluid stream constant and permits a fluid stream to flow toward the utilization device while dissipating any downstream feedback or disturbance. The feedback isolator comprises a pair of emitter nozzles 90 and 92, a pair of collectors 94 and 96 aligned with their respective emitter nozzles in a stream intercepting relationship, and a constant pressure chamber 98 intermediate said nozzles and said collectors, said chamber being vented to ambient.

As heretofore noted, and as will be readily understood by one familiar with the art, the fluid operated device of this invention can be employed as an analog signal to digital signal converter in an apparatus such as a digital computer. Referring again to FIGURE 1, the apparatus illustrated can be used as an analog to digital converter by maintaining the settings of control valves 54 and 82 constant while obtaining variable frequency output signals from the apparatus at outlets 84 and 86 solely by varying the input pressure to inlet 11. The settings of control valves 54 and 82 are maintained constant to permit the operation of diaphragm valves 24 and 26, and consequently the timing intervals of the apparatus, to be dependent solely on the upstream pressure. Similarly, variable frequency output signals can be obtained by changing the load or downstream resistance while maintaining a constant pressure to inlet 11 and constant settings of valves 54 and 82.

Referring now to FIGURE 3, there is illustrated a constricted tube 100 which is suitable for replacing control valves 54 and 82 to maintain the operation of the diaphragm valves dependent solely on the upstream pressure as hereinabove described. Similarly an orifice 102, illustrated in FIGURE 4, may be substituted for control valves 54 and 82 for the same purpose.

It is further seen that although the apparatus of this invention has been described with one fluid amplifier, a plurality of amplifiers can be staged or connected so that the output of one diaphragm valve is fed to a control fluid nozzle of a second amplifier, and so on, with the output of the last diaphragm valve being connected to the control fluid nozzle of the first amplifier, thereby providing an apparatus having a cycle of more than two time intervals.

As will be readily understood by one familiar with the art that, although the invention has been described in terms of separate components connected by tubes or members, the apparatus of this invention can be made of integrally formed or molded parts wherein the tubes are merely passages within such parts.

Although the present invention has been described with respect to specific details of certain embodiments thereof, it is not intended that such details be limitations upon the scope of the invention except insofar as set forth in the following claims.

We claim: 1. A fluid operated apparatus for providing signals at predetermined time intervals comprising a fluid amplifier of the type having interconnected fluid passages whereby a well defined, high energy fluid stream may flow from an inlet aperture to one of two outlet passages, control means for alternately switching the fluid stream from one of said outlet passages to other of said outlet passages, first and second apparatus outlet means, means for alternately directing a first portion of said fluid stream to the first of said apparatus outlet means and then to the second of said apparatus outlet means in response to said control means, fluid operated means for measuring a predetermined volume of a second portion of said fluid stream at a regulated rate such that said volume will be measured in a predetermined desired interval of time, said control means being responsive to said fluid operated means such that said control means cause said fluid stream to switch to the other of said outlet passages when said volume is measured, and means for resetting said fluid operated means. 2. The apparatus of claim 1 wherein said fluid amplifier is a bistable fluid amplifier.

3. The apparatus of claim 2 wherein said fluid operated means comprise a two-stage diaphragm valve.

4. The apparatus of claim 3 wherein said fluid operated means further comprise a fluid flow control valve.

5. The apparatus of claim 3 wherein said fluid stream is air.

6. The apparatus of claim 3 wherein said fluid operated means further comprise a constricted tube.

7. The apparatus of claim 3 wherein said fluid operated means further comprise an orifice.

8. A fluid operated apparatus for providing signals at predetermined time intervals comprising a bistable fluid amplifier of the type having interconnected fluid passages whereby a well defined, high energy fluid stream may flow from an inlet aperture to one of two outlet passages, first control means for alternately switching the fluid stream from one of said outlet passages to the other of said outlet passages, first and second apparatus outlet means, means for alternately directing a first portion of said fluid stream to the first of said apparatus outlet means and then to the second of said apparatus outlet means in response to said first control means, a diaphragm valve for measuring a predetermined volume of a second portion of said fluid stream, second control means for regulating the rate of flow of at least a portion of said second portion of said fluid stream such that said predetermined volume will be measured in a predetermined desired period of time, said first control means being responsive to said diaphragm valve such that said first control means cause said fluid stream to switch to the other of said outlet passages when said volume is meas ured, and means for resetting said diaphragm valve.

9. The apparatus of claim 8 wherein said second control means is a valve.

10. The apparatus of claim 8 wherein said second control means is a constricted tube.

11. The apparatus of claim 8 wherein said second control means is an orifice.

12. The apparatus of claim 8 further comprising a feedback isolator intermediate said amplifier outlet passages and said first and second apparatus outlet means.

13. A fluid operated apparatus for providing signals at predetermined time intervals comprising a bistable fluid amplifier of the type having interconnected fluid passages whereby a well defined, high energy fluid stream may flow from an inlet aperture to one of two outlet passages,

first and second control means for alternately switching the fluid stream from one of said outlet passages to the other of said outlet passages,

first and second apparatus outlet means,

means alternately directing a first portion of said fluid stream to the first of said apparatus outlet means and then to the second of said apparatus outlet means in response to said first and second control means,

a first two-stage diaphragm valve having first and second stage pressurizing chambers, said valve being connected intermediate said one of said outlet passages and said first control means such that a second portion of said fluid stream flows to each of said pressurizing chambers,

a first control valve connected intermediate said one of said outlet passages and said second stage pressurizing chamber, said first control means being responsive to said first diaphragm valve such that said fluid stream is switched to said other of said outlet passages in a predetermined desired first interval of time,

a second two-stage diaphragm valve having first and second stage pressurizing chambers, said valve being connected intermediate said other of said outlet passages and said second control means such that said second portion of said fluid stream flows to each of said pressurizing chambers of said second two-stage diaphragm valve when said fluid stream is switched to said other of said outlet passages,

a second control valve connected intermediate said other of said outlet passages and said second stage pressurizing chamber of said second two-stage diaphragm valve, said second control means being responsive to said second diaphragm valve such that said fluid stream is switched to said one of said outlet passages in a predetermined desired second interval of time, and

means for resetting each of said diaphragm valves.

14. The apparatus of claim 13 further comprising a first means for connecting said one of said outlet passages to said first stage pressurizing chamber,

first fluid flow regulating means connected intermediate said one of said outlet passages and said second stage pressurizing chamber,

second means for connecting said second stage fluid flow control chamber to said first control means,

first apparatus outlet means connected intermediate said one of said outlet passages and said first stage pressurizing chamber,

a second two-stage diaphragm valve having third and fourth stage pressurizing chambers and third and fourth stage fluid flow control chambers, said third stage fluid flow control chamber being connected to said fourth stage pressurizing chamber and also being vented to ambient, said fourth stage fluid flow control chamber also being vented to ambient,

third means for connecting said other of said outlet passages to said third stage pressurizing chamber,

second fluid fiow regulating means connected intermediate said other of said outlet passages and said fourth stage pressurizing chamber,

fourth means for connecting said fourth stage fluid flow control chamber to said second control means,

second apparatus outlet means connected intermediate said other of said outlet passages and said third stage pressurizing chamber,

means for resetting each of said diaphragm valves, and

said apparatus pr viding signals alternately at each of said first and second apparatus outlet means at predetermined desired intervals of time, said intervals of time being at least in part controlled by said first and second fluid flow regulating means.

16. The apparatus of claim 15 wherein said fluid stream is air.

17. The apparatus of claim 15 wherein said first and second fluid flow regulating means are valves.

18. The apparatus of claim 15 wherein said first and second fluid flow regulating means are constricted tubes.

19. The apparatus of claim 15 wherein said first and second fluid flow regulating means are orifices.

20. The apparatus of claim 15 further comprising a feedback isolator intermediate said amplifier outlet pasfeedback isolator intermediate said amplifier outlet passages and said first and second apparatus outlet means.

sages and said first and second apparatus outlet means.

15. A fluid operated apparatus for providing signals at predetermined time intervals comprising a bistable fluid amplifier comprising a plurality of interconnected fluid passages whereby a well defined, high References Cited UNITED STATES PATENTS 2,984,218 5/1961 Christianson 137-82 X energy fluid stream may flow from an inlet aperture 3 117 593 1/1964 Sewer 137 81 5 X to one of two outlet passages, 3150674 9/1964 0 "i 82 first and second control means for alternately switch- Onnaug t ing said fluid stream from one of said outlet pas- 3159168 12/1964 Reader 137*81'5 sages to the other of said outlet passages, 3181547 5/1965 Bennett 137 82 a first two-stage diaphragm valve having first and sec- $185,166 5/1965 Horton et a1 137 81-5 ond stage pressurizing chambers and first and second 3,203,448 9/ 1965 WOOdWard 1'5 X stage fluid flow control chambers, said first stage 3,217,727 11/1965 PY P fluid control chamber being connected to said sec- 3,232,305 2/1966 Groeber 13781.5 ond stage pressurizing chamber and also being 3,270,758 9/1966 Bauer 137-81.5

vented to ambient, said second stage fluid flow control chamber also being vented to ambient, SAMUEL SCOTT, Primary Examiner. 

